Fabrics for therapeutic skin care bedding

ABSTRACT

A fabric for bedding which includes a woven fabric having warp yarns and filling yarns woven to provide a smooth fabric surface. One of the warp or filling yarns being at least 40% by weight of the fabric of continuous filament nylon, and the other of the warp or filling yarns being from about 0% to 60% by weight of the fabric of continuous filament polyester or nylon having non-round filament cross sections. An antimicrobial substance is topically applied or inherently available in the fabric.

The present application is a continuation in part of U.S. patentapplication Ser. No. 10/985,739 filed Nov. 10, 2004, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates generally to therapeutic bedding, and morespecifically to bedding that includes a woven fabric havingantimicrobial properties and dries quickly to aid in healing dermatitisand other skin ailments. A similar fabric for therapeutic skin carebedding is disclosed in U.S. patent application Ser. No. 10/985,739filed Nov. 10, 2004, now abandoned the entire disclosure of which ishereby incorporated by reference.

A significant portion of the world's population is afflicted with skinproblems. Nearly 15 million Americans have eczema, a chronic skincondition marked by itchy, red patches of inflamed skin. Six to sevenmillion Americans have psoriasis, which is a skin disease that causesunsightly sores and skin scales. Such skin diseases account for a largeportion of annual healthcare costs. For instance, psoriasis accounts forabout $3 billion dollars a year in healthcare costs. Further, the directfinancial cost in the care of a child with moderate or severe eczema issubstantially higher than that for the average child with asthma.

There are also non-financial costs associated with the time spent intreatment and sleep deprivation. Between two and three hours each day isgenerally spent treating eczema, and an average of one to two hours ofsleep each night is interrupted. Indeed, skin problems impact thequality of life for both sufferers and their families.

In addition to the effects of intractable itching, skin damage,soreness, sleep loss, and the social stigma of a visible skin disease,other factors add to the burden of the disease. The standard treatmentsfor chronic skin problems involve the routine application ofantibacterial ointments to reduce the potential for infections. Othertreatments include the avoidance of clothing made of irritating wool ornatural fibers and the use of non-aggressive detergents on clothing andbedding. Many must also control environmental conditions to maintain theproper level of moisture on the affected skin.

Skin irritations and dermatitis are exacerbated by two factors: exposureof skin to excessive moisture, and the potential for shear forceinjuries caused by friction with apparel or bedding. Although othersubstances, such as urine, stool, perspiration or wound drainage, maycontain factors other than moisture that irritate the skin, moisturealone can predispose the skin to serious injury. Friction burns on theskin frequently occur when a person moves across a coarse moist surfacesuch as bed sheet.

Although solutions involving wearing apparel are commonly available tohelp alleviate skin problems, effective technologies relating to bedlinens have not been readily available. There are some examples oftherapeutic bedding; however they have limitations in their ability tofully address the problems associated with skin injuries. An intriguingexample of skin-care apparel involves a line of products marketed underthe trade name DermaSilk™. The DermaSilk technology has shown excellentclinical results in helping to heal atopic dermatitis and psoriasis, aswell as skin ulcers that form as a result of diabetes. DermaSilktherapeutic apparel include undergarments and body wraps knitted of 100%silk yarns and treated with a durable antimicrobial agent.

Silk is effective in this case since silk fibers have a chemicalstructure very similar to that of human hair (97% protein, 3% fat, andwax matter). Silk fibers are perfectly smooth and cylindrical. As such,they do not create mechanical friction with the skin. Further, silk isnaturally hygroscopic, absorbing up to 30% of its own weight in sweatwithout becoming wet. This is important in aiding the cure of atopicdermatitis because silk is able to maintain the moisture balance of theskin, providing a softening and soothing micro-climate next to the skin.Silk is also capable of absorbing and releasing moisture without causingirritation, because the diameter of silk's cylindrical fibers simplyincrease or decrease as moisture is absorbed or released. Since silkyarns are made up of tiny continuous filaments, delicate skin is notdisturbed as the moisture content changes. Silk helps to reduce heavysweating (common in children affected by atopic dermatitis), as well asminimize the loss of moisture that can aggravate skin dryness anditching. Silk is also naturally elastic. When used in a knittedconstruction, silk fabrics allow garments to move with the body and toremain closely bound to the skin, thereby reducing friction.

Derma Silk fabrics and apparel also incorporate a topical antimicrobialagent that provides protection to the silk fibers against a broad rangeof bacteria, germs, molds, and fungus. This antimicrobial treatmentinhibits the survival of bacteria on the fabric and is highly effectiveagainst Staphylococcus Aureus, one of the major factors of worseningatopic dermatitis.

While silk has been proven effective in apparel and body wraps, thereare inherent deficiencies in the use of silk fibers, yarns, and fabricsas they relate to therapeutic bed linens, such as pillowcases andsheets. Unlike knitted apparel and wraps, bed sheets and pillowcasesmust withstand continuous use of up to 8 to 9 hours per day, andextensive laundering and drying. Bedding is typically subjected tovarious chemicals and stains associated with personal hygiene. Further,bedding must withstand much greater stresses and strains associated withsleeping adults. Chloride salts in perspiration and deodorants weakensilk. Also, alcohol-based products such as hairspray and perfumes, andchemical products like nail polish remover easily damage silk fabrics.Water applied to a stain on silk can set the stain or cause a permanentstain ring. Silk cannot be presoaked in detergents or bleaches; as bothwill damage silk. Further, silk fabrics cannot be air-dried in the sun,since ultraviolet rays degrade silk. Therefore, silk fabrics areinappropriate for use in therapeutic bed linens.

Thus there remains a need for a non-abrasive bed linen withantimicrobial properties that may aid in the healing of skin diseasesand the prevention of further skin irritation. Further, there remains aneed for a cost effective bed linen that does not irritate or exacerbatea patient's dermatitis, and can withstand many washings, detergents,autoclaving, irradiation, and nightly wear as necessary.

SUMMARY OF THE INVENTION

The present invention fulfills one or more of these needs in the art byproviding a fabric for bedding that involves a unique combination ofpolymer types and fiber configurations to form woven fabrics that arelike silk in terms of aesthetics, smoothness, elongation, and moisturehandling, but more durable, more stain resistant, and more suitable forbedding. Further, the present invention also is superior tocotton-containing fabrics because the fabric dries quickly and stayssmooth when wet.

The present invention is directed to a fabric for bedding which includesa woven fabric having warp yarns and filling yarns woven to provide asmooth fabric surface. In the preferred embodiment, one of the warp andfilling yarns may be at least 40% by weight of the fabric of continuousfilament nylon. The other of the warp and filling yarns may be fromabout 0% to 60% by weight of the fabric of continuous filament polyesteror nylon having non-round filament cross sections. Preferably, anantimicrobial substance is topically applied or inherently available inthe fabric.

Also, the warp yarns may be 100% nylon, and the filling yarns may bepolyester or nylon.

The fabric is preferably woven as a twill weave or plain weave. The warpyarn may be a 40 denier, 34 filament, five twist per inch, continuousfilament nylon 6-6 yarn, with the filling yarn a 75 denier, 48 filament,continuous filament textured polyester. In the most preferredembodiment, the warp yarn is a 70 denier, 48 filament, continuousfilament nylon yarn, with the filling yarn a 75 denier, 36 filament,continuous filament textured polyester.

Preferably, the continuous filaments have a non-round fiber crosssection, such as a star shaped cross section or a clover leaf crosssection. The continuous filaments with non-round fiber cross sectionstypically have a cross section such that adjacent filaments form wickingchannels that enhance moisture wicking and rapid drying.

Also preferably, the fabric is finished to produce a fabric with anelongation greater than about 30% per ASTM D5034-95 test for breakingstrength and elongation of textile fabrics.

In the preferred embodiment, the fabric has a soil-release topicalfinish.

In one aspect, the present invention provides a sheet for a bed madewith a woven fabric having warp yarns and filling yarns woven to providea smooth fabric surface and sized to cover a bed. The sheet may havehems to prevent raveling of the woven fabric. Preferably, one of thewarp and filling yarns is at least 40% by weight of the fabric ofcontinuous filament nylon, and the other of the warp and filling yarnsis from about 0% to 60% by weight of the fabric of continuous filamentpolyester or nylon having non-round filament cross sections. Preferably,an antimicrobial substance is topically applied or inherently availablein the fabric.

Another aspect of the present invention is to provide a pillow case madewith a woven fabric that has warp yarns and filling yarns woven toprovide a smooth fabric surface. The pillow case is sewn to form apocket to encase a pillow with an opening on one end to enable insertionof the pillow therein. One of the warp and filling yarns may be at least40% by weight of continuous filament nylon, and the other of the warpand filling yarns may be from about 0% to 60% by weight of continuousfilament polyester or nylon having non-round filament cross sections. Inthe preferred embodiment, an antimicrobial substance is topicallyapplied or inherently available in the fabric.

Still another aspect of the present invention is to provide atherapeutic bedding fabric including woven fabric that has warp yarnsand filling yarns woven to provide a smooth fabric surface. The warp andfilling yarns are continuous and substantially free of hairiness. One ofthe warp and filling yarns is preferably a continuous filament yarnhaving a non-round filament cross section such that adjacent filamentsform wicking channels. An antimicrobial substance may be topicallyapplied or inherently available in the fabric.

An invention can also be considered as providing a method of patienttherapy including covering the patient's bed with sheets having smoothsurfaces even when wet; and allowing the patient to rest between thesheets. The surface roughness between the sheets and the patient's skinis reduced in comparison with the surface roughness that would existbetween cotton or polyester/cotton blend fabric sheets and the patient'sskin.

Desirably, the method includes the sheets having an average geometricsurface roughness of 1.0 to 1.75 microns when dry as measured by theKawabata Evaluation System FB4 Surface Tester. Preferably the sheetsprovide an antimicrobial efficacy against E. Coli, Staph. Aureus, Staph.Epidermidis, and P. Aeruginosa in at least one of the sheets of at least94%. More preferably, the sheets provide an antimicrobial efficacyagainst E. Coli, Staph. Epidermidis, and P. Aeruginosa in at least oneof the sheets of at least 99.4%

These and other aspects of the present invention will become apparent tothose skilled in the art after a reading of the following description ofthe preferred embodiment when considered with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a bed covered with a sheet and a pillowcovered with a pillowcase as disclosed in the present invention;

FIG. 2 is a photomicrograph of a yarn with a star-shaped fiber crosssection useful in one embodiment of the invention; and

FIG. 3 is a photomicrograph of a yarn with a cloverleaf-shaped fibercross section useful in an embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A fabric for bedding is formed with a woven fabric having warp yarns andfilling yarns woven to provide a smooth fabric surface. In the preferredembodiment, one of the warp or filling yarns is at least 40% by weightof the fabric of continuous filament nylon. The other of the warp orfilling yarns may be from about 0% to 60% by weight of the fabric ofcontinuous filament polyester or nylon having non-round filament crosssections.

Preferably, an antimicrobial substance is topically applied orinherently available in the fabric. In the preferred embodiment, anantimicrobial substance such as AEGIS Microbe Shield, manufactured byAEGIS Environments, Inc. is topically applied to the woven fabric in astandard textile finishing operation. This antimicrobial works bestagainst the following common microbes: Escherichia Coli, StaphylococcusAureus, Staphylococcus Epidermidis, Pseudomonas Aeruginosa. Theantimicrobial substance may also prevent odors in the fabric.

In a preferred embodiment, the warp yarns may be 100% nylon, and thefilling yarns may be polyester or nylon.

In one embodiment, the fabric is woven as a twill weave (typically a 2×1twill) or plain weave. Yarns are woven into fabric constructions thathave 80% to 100% coverage. The warp yarn may be a 40 denier, 34filament, five twist per inch, continuous filament nylon 6-6 yarn, andthe filling yarn may be a 75 denier, 48 filament, continuous filamenttextured polyester. In another embodiment, the warp yarn is a 70 denier,48 filament, continuous filament, textured nylon, and the filling yarnis a 75 denier, 36 filament, continuous filament, textured polyester.Continuous filament yarns are preferred because those yarns do not haveshort fibers extending beyond the fabric's planar surface, therebydecreasing irritation to sensitive skin. The smooth fabric surface alsoaccentuates this effect. In the alternative, warp yarns of about 30denier to 100 denier, and filling yarns of about 30 denier to 100 deniermay be used.

Preferably, the continuous filament has non-round fiber cross-sectionssuch as a star shaped cross section or a clover leaf cross section. Theclover-leaf cross section also improves the fabric's smoothness andsoftness. Examples of these are seen in FIGS. 2 and 3. With non-roundfiber cross sections adjacent filaments form wicking channels alongfiber surfaces to promote and enhance moisture transport away fromcontact with the skin. Thus, moisture more quickly evaporates and driesfrom the fabric surface, reducing the amount of moisture contacting theskin. As such, the wicking channels also help the user to maintain bodytemperature by reducing excess sweating.

In the preferred embodiment, nylon is used because it has one of thehighest moisture regains of any synthetic fiber. Nylon absorbs moisture,and aids in wicking and evaporation. Although nylon is preferred,polyester can also be used if a durable auxiliary hydrophilic treatmentis applied as a post finish.

In the preferred embodiment, the fabric may also contain a soil-releasetopical finish. Thus, the fabric is able to release stains associatedwith skin antibiotic creams and ointments.

As seen in FIG. 1, a sheet 10 for a bed is made with a woven fabrichaving warp yarns and filling yarns woven to provide a smooth fabricsurface and sized to cover a bed. The sheet 10 may have hems 14 toprevent raveling of the woven fabric. Preferably, one of the warp orfilling yarns is at least 40% by weight of the fabric of continuousfilament nylon, and the other of the warp and filling yarns is fromabout 0% to 60% by weight of the fabric of continuous filament polyesteror nylon having non-round filament cross sections. An antimicrobialsubstance is topically applied or inherently available in the fabric.

Also as seen in FIG. 1, a pillowcase 12 is made with a woven fabric asdescribed above. The pillowcase 12 is sewn to form a pocket to encase apillow with an opening 16 on one end to enable insertion of the pillowtherein. One of the warp or filling yarns is at least 40% by weight ofthe fabric of continuous filament nylon, and the other of the warp orfilling yarns is from about 0% to 60% by weight of the fabric ofcontinuous filament polyester or nylon having non-round filament crosssections. In the preferred embodiment, an antimicrobial substance istopically applied or inherently available in the fabric.

Preferred fabrics have the following properties:

-   -   High moisture regain. Nylon, with one of the highest moisture        regains of any synthetic fiber, absorbs moisture and aids in        wicking and evaporation.    -   Excellent moisture transport. Non-round fiber cross sections        create channels along fiber surfaces to promote and enhance        moisture transport away from contact with the skin. Moisture        more quickly evaporates and dries, and thereby reduces the        amount of wetness next to the skin. As such, it helps the user        to maintain body temperature by reducing excess sweating.        Preferably, the fabric is 100% dry after 1 hour.    -   Minimal friction with the skin. Continuous-filament yarns have        no short fibers extending beyond the fabric's planar surface to        irritate sensitive skin. A smooth fabric surface accentuates        this effect. Preferably, the fabric has an average geometric        roughness of less than about 1.7 microns as measured by the        Kawabata Evaluation System FB4 Surface Tester.    -   A good degree of stretch and recovery. Such fabrics help bed        sheets to fit tighter and thereby reduce wrinkling that causes        skin irritation. Such fabrics also better conform to the body        and reduce the shear forces on sensitive skin. Preferably, the        fabric is finished to produce a fabric with an elongation        greater than about 30% as measured by ASTM D5034-95.    -   Durability to extended laundering and drying. Such fabrics will        not loose fibers during laundering (in comparison with cotton        blends), and are not afflicted with fiber pills that further        irritate skin.    -   Able to withstand high wash temperatures and the use of harsh        detergents.    -   Able to release stains associated with skin antibiotic creams        and ointments.    -   Antibacterial efficacy against the survival of S. aureus,        fungus, and molds on the fabric surface. Odors are prevented.        Preferably, the fabric has an antimicrobial efficacy against E.        Coli, Staph. Epidermidis, and P. Aeruginosa of at least about        99.4% per AATCC 100.

The data for the yarns of FIGS. 2 and 3 are compared with typical 55/45polyester/cotton and 100% cotton bedding fabrics in Table I below.

TABLE I FIG. 2 FIG. 3 Preferred Conventional Conventional Units yarnyarn Embodiment Sheet Sheet Warp Yarn 40/34 40/34 70/48 55/45 100% 7zNylon 7z Nylon textured Poly/cotton Cotton nylon Fill Yarn 75/48 70/7275/36 55/45 100% textured textured textured Poly/cotton Cotton polyesternylon polyester Fabric Weight osy 2.53 2.51 2.43 3.72 3.44 Yarns perInch, epi 180 173 102 111 113 machine direction Yarns per Inch ppi 110107 104 79 84 cross-machine direction Avg. Elongation % 37.6 37.4 39.617.2 12.8 Air Permeability cfm/ft² 10.7 9.2 30.5 39.5 39.4 Circular BendN 0.7 0.6 0.3 0.9 0.7 Thermal Insulation Value Clo 0.49 0.50 n/a 0.530.55 Soil Release to Oily Stains 3.0 2.5 5.0 3.5 3.0 Kinetic Coefficient0.53 0.35 0.22 1.10 1.00 of Friction (COF) - Warp direction KineticCOF - Fill 0.50 0.56 0.23 1.08 1.03 Avg. Surface Roughness μ 1.4 1.1 1.53.7 2.3 Fabric Dryness after 1 hour % 100% 100% 100% 51%  52%

Certain modifications and improvements will occur to those skilled inthe art upon a reading of the foregoing description. For example, theinvention may be carried out with weaves other than plain weaves ortwill weaves. The weaves of the invention create a smooth flat surface,without any three-dimensional surface structures that might undulyabrade skin. Other weaves that could be substituted include satin,sateen, or duck weaves. It should be understood that all suchmodifications and improvements have been deleted herein for the sake ofconciseness and readability but are properly within the scope of thefollowing claims.

1. A sheet for a bed comprising: a woven fabric having warp yarns andfilling yarns, wherein the warp yarns are about 30 denier to 100 denier,and the filling yarns are about 30 denier to 100 denier, wherein thewarp yarns and filling yarns are woven together in a plain weave toprovide a pill resistant fabric having identical surfaces on both sidesthereof, wherein the sheet is sized to cover a bed and having hems toprevent raveling of the woven fabric; one of the warp or filling yarnsbeing 100% continuous filament nylon and making up at least 40% byweight of the fabric; the other of the warp or filling yarns beingcontinuous filament polyester or nylon having non-round filament crosssections and making up the remainder of the weight of the fabric; and anantimicrobial substance topically applied or inherently available in thefabric.
 2. The sheet as claimed in claim 1 wherein the fabric has anaverage geometric surface roughness of about 1.0 to 1.75 microns whendry as measured by the Kawabata Evaluation System FB4 Surface Tester. 3.A pillow case comprising: a woven fabric having warp yarns and fillingyarns, wherein the warp yarns are about 30 denier to 100 denier, and thefilling yarns are about 30 denier to 100 denier, wherein the warp yarnsand filling yarns are woven together in a plain weave to provide a pillresistant fabric having identical surfaces on both sides thereof,wherein the fabric is sewn to form a pocket to encase a pillow with anopening on one end to enable insertion of the pillow therein; one of thewarp and filling yarns being 100% continuous filament nylon and makingup at least 40% by weight of the fabric; the other of the warp andfilling yarns being continuous filament polyester or nylon havingnon-round filament cross sections and making up the remainder of theweight of the fabric; and an antimicrobial substance topically appliedor inherently available in the fabric.
 4. A method of patient therapy,comprising: covering a bed with sheets; and allowing a patient to restbetween the sheets, wherein each sheet comprises a woven fabric havingwarp yarns and filling yarns woven to form a pill resistant fabrichaving identical surfaces on both sides thereof, wherein one of the warpor filling yarns is at least 40% by weight of 100% continuous filamentnylon, wherein the other of the warp or filling yarns is continuousfilament polyester having non-round filament cross sections orcontinuous filament nylon having non-round filament cross sections, andan antimicrobial substance topically applied or inherently available inthe fabric.
 5. The method of claim 4, wherein the continuous filamenthaving non-round filament cross sections has a cross section such thatadjacent filaments form wicking channels.
 6. The method of claim 4,wherein the fabric exhibits a percent (%) dryness after 1 hour of 100%.7. The method of claim 4, wherein each surface of the woven fabric hasan average geometric surface roughness of about 1.0 to 1.75 microns whendry as measured by the Kawabata Evaluation System FB4 Surface Tester.